I have a King 8". My brother in law had a King 6". They are good machines.
Even though the one you are looking at has low hours, run a straight edge all the way along the in-feed / out-feed tables. With the in-feed table all the way up, the straight edge should make consistent contact all the way across.
If the current owner started using it as a table, a continuous consistent weight on the ends can bow the casting over time.
I don't know how it compares to my KC-6JC, maybe newer, but I am satisfied with it. Not too powerful but works great for what I need it for.
Paid $200 about 10 years ago. I believe mine is a 1991 model.
I have been looking for a manual for a while but have not been able to find one.